Rubber slug for condenser tubes



RUBBER SLUG FOR CONDENSE R T U B ES Patented Apr. 28, 1931 WILLIAM F. OBERHUBER, or LANSIDOWNE,

PENNSYLVANIA, ASSIGNOR To FRANKLIN DEVELOPMENT COMPANY, or rz-rrnnnnnrrrrs, PENNSYLVANIA, A coRroRA'rioN OF PENNSYLVANIA lnUBBE -t SLUG son Application filed February My invention relates to slugs for cleaning condenser tubes and the like, to be driven through the tubes preferably by compressed air or water. i

A purpose of my invention is to interiorly flare the forward end of a rubber slug in order to increase the tightness withwhich it fits a tube through which it is being driven and to discharge the driving fluid through the tube and against tube deposit to the best advantage.- I o A further purpose is to internally flare the rear end of the slug so as to swell it against the tube by the driving fluid, flaring it preferably to a lesser extent than the forward end. 1

A further purpose is to internally rifle the bore of a rubber slug in order to make its action more effective. a

A further purpose is to internally wedge a rubber slug to expand it againsta tube.

Further purposes will appear in the specification and in the claims.

I have preferred to illustrate my invention by one main form only, with minor Inodifica--v tions, and have selected a form that is practical, efficient, inexpensive, simple in manufacture, and that at the same time well illustrates the principles involved.- 7

Figure 1 is a fragmentary longitudinal section of a tube and aslug in the tube,

Figure 2 is a side elevation of the slug, seen in Figure 1;

.tions showing modified forms.

Figure 3 is an end elevation of Figure 2.-

Figurefia 1s an end elevation of the struc-,

ture sectioned in Figure 4.

Figures 4, 5, 6 and 8 are longitudinal sec- Figure 7 is a section of Figure 4 upon line i In the drawings similar'numerals indicate like parts. t r a Describing in illustration and not in limitation, and referring tothe drawings Prior to my present invention slugs of rubber or elastic material have been used forv cleaning condenser tubes and the like, 7 of which a number of forms are shown in my apv plications N 0. 748,435, auxiliary spring plugs for condenser tubes, and No. 572,570 for CONDENSER TUBES 2, 1926. Serial No. 85,533.

mithod and apparatus for cleaning condenser tu es. 1

I'have discovered thatit isquite advantageous to internally bell or flare the forward end of the slug forwardly andthat when this is done the contact between the front portion of the slug and a tube through which} it is being driven is very much more close; than when the slug is notthus forwardly flared. Thistight gripping between the circu1nferen-. tial forward end of the slug and the'internal surface of the tube through which it is being driven is doubtlessdue to longitudinal compression throughout the bodyofthe slug resulting from driving the slug throu h the tube'against resistance at the circumference offered by dirt of the tube. v v In belling or flaring the forwardend of the 7 tube I am able to secure another and marked advantage illustrated in Figures 1% by suiting the bell or flare to-nozzle purposes, enlarging it forwardly so as to apply the driving fluid as abruptly as possible against the interior of the tube at or shortly in advance of the forward outer edge of the slug. This nozzle is particularly advantageous when air or other gas or vapor is ,used as a driving fluid because of the continued expansion and acceleration of the gas or' vapor, which strikes the interior of the tube athigh velocity and cuts the deposit at the edge or in advance of the passage of the slug or bothaccording to the flare and the pressure asis well understood in arts using expanding nozzles. 7

Independently of this action the blast of fluid through the slug tends to clearout the deposit which hasbeen loosenedso as to relieve against clogging of the tube. 7 1

I' also desirably internally flare the, rear end of the slug rearwardly, but preferably to a lesser extent than the forward end; I This internal flare of the rear end of the slug serves the double purpose of permitting fluid pressure within the rearward cupped portion to expand the elastic material of the slug against the tube, and of making the approach to the opening through the slug more nearly thatproper for a nozzle.

Referring to the figures Fr The slug prefer= ably comprises a single homogeneous mass of molded rubber 8. The forward interiorly flared end takes the form of an expanding nozzle for high pressure air or other expanding fluid. The diameter at the forward endis preferably slightly greater than that of the tube 9 in which the slug is designed to be used.

As the slug is driven through the tube the material throughout the length of the slug is compressed by reason of the resistance offered to its motion by friction against the tube interior and by engagement at 10 with the dirt within the tube. As they resistance at the front edge presses the slug rearwardly the driving fluid presses it forwardly resulting in strong outward pressure against the surface of the tube, and corresponding greater friction against the tube and more efiective cleaning. 7

Y The same slug reversed will go through the tube relatively easily while even through a clean tube when being driven in the direction indicated by the arrow I find that the contact between the forward end and the inner surface of the tube is a very strong one.

In the form shown in Figures 3a and 4 I internally rib or groove the bore of the slug at 11 as in rifling giving the rib or groove a spiralform for the double purpose of causing rotation of the slug and of more effectively distributing the driving fluid against the interior of the tube.

Obviously the outward pressure against the tube is greatly increased by the pressure of the driving fluid. This pressure is greatest at the rear end and progressively diminishes forwardly along the bore of the slug.

The advantageous forward flaring may be used to obtain additional friction whether or not the slug be longitudinally perforated, and this is illustrated in Figures 5 and '6.

Though I prefer to have the slug longitudinally perforated and flared rearwardly to efiect tight expansion against the tube at the rear end of the slug as well as flaring for-.

wardly to permit longitudinal compression responsive to resistance offered upon the outer circumference of the slug, I show in Figure 6 l aformin'which both the rearwardcupping and the longitudinal perforation have been omitted.

The aperture 12 andparticularly the flare of the opening at the rear of the aperture facilitates the expansion of the central part ofmy slug against the tube whether the for- "ward end of the slug be belled' to increase the pressure there or not. I have already pointed out that the pressure of the fluid tends 6b to expand the entire slug and that the belling the effectlveness of this expansion at the rear of the rearward portion of the slug increases end. In Figures 4, 7 and 8 I show mechanical means for expanding the central part of the slug in a wedge 18. The wedge is also shown in Figure 7.

In the form of Figure 7 the wedging takes place at an interior point 14 only and the presence of the ribs 11 permits passage of driving fluid through a portion of the opening 12, notwithstanding the presence of the wedge. Spiral streams of driving fluid pass through outside the wedge.

In the form shown in Figure 8 the wedge 13 is forced by the fluid pressure into'a different opening 12 which tapers throughout nearly the whole length of the slug permitting expansion of an otherwise solid slug body throughout substantially its entire length. By the shape of the rear end of the wedge the rear of the flare of the slug will also be expanded. I

In this form of Figure 8 the expanding operation is almost wholly mechanical.

In view of my invention and disclosure variations and modifications to meet individual whim or particular need will be evident to others skilled in the art which will attain all or a part of the benefit of my invention without copying my illustrations and I therefore claim all such in so far as they fall within the reasonable spirit and scope of my invention. I

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. A longitudinally perforated rubber slug for cleaning condenser tubes and the like, said perforation internally flaring toward the forward and rearward ends of the slug.

2. A longitudinally perforated rubber slug for cleaning condenser tubes and the like, the perforation flaring toward the forward end.

3. A slug for cleaning condenser tubes and the like, having a longitudinal perforation, said perforation flaring toward the front and toward the rear, the forward flare being longer than the rearward.

4. A perforated rubber slug for cleaning condenser tubes and the like, internally rifled to make it rotate during its passage through a condenser tube.

5. A rubber slug for cleaning condense tubes and the like, having a longitudinal perforation, said perforation flaring forwardly and rearwardly and having rifling upon its interior.

6. A rubber slug for cleaning condenser tubes having a central tapered opening in combination with a wedge fitting in the opening and adapted to be driven into it by the operating fluid to spread the slug against the interior of the condenser tube.

7. A device of the character described comprising a rubber slug having end walls and also having side walls "adapted for engagement with the inner walls ofcondenser tubes, there being an opening through the slug between the end walls, and a plug having a dimension larger than a minimum dimension of the opening," inserted in the opening with the cross sections of the slug opening and the plug not in registering relation, whereby upon fluid propulsion of the device, the plug expands the slug and the driving fluid passes through the slug.

WILLIAM F. OBERHUBER. 

